My turn, 15k isnt enough I can tell you that right now. Ive went down this road already, and plan on building on my own in the near future with a few ppls help. Here's a basic idea.
Rods 2500-4000 your stock rods aint gonna hold to well at 1000hp.
Injectors 2500-3500 depending who you go with and what size they are.
Fuel systems 500-1000 also depending how you plan on setting it up.
Turbo kits range 7000-10,000 as a daily driver your gonna spend money.
Intake manifold this I'd look into Doug's at GoGo 1200 for better flow the back cylinders will starve.
Transmission 5000 for a fully built, the working internally.
Thats most of the basic parts, none of which include labor in doing the work, cost of core charges, your stock pistons will only hold so much as well. Then you'll need to look into harden valve seats, valve springs, heads, cams, hhmmm what else. Unless you can do all the work yourself, and have money when it breaks and tear down the motor I wouldnt step into this realm.
Sorry for the negativity but its facts.
Forgot to add and to do a good clean cummins swap with performance parts uh your looking at 20k plus.